As someone who doesn't remember 9/11, my opinion is that most of the movies and music from the 80s/90s (yes, especially the popular ones) are terrible and that the majority of media I enjoy was produced in the last 20 years. I think people tend to like whatever they heard and saw during their formative years.
Well good, this gives me hope that I've just become the crotchety old guy that complains about how things aren't as good as they used to be (even though I promised myself I wouldn't become that guy when I was young), rather than the world is going towards more and more Idiocracy.